Many commercial chairs, such as pedestal-type office chairs, utilize a fluid (more specifically a pneumatic) height-adjusting mechanism for permitting the height of the seat assembly to be adjusted to accommodate the user. These mechanisms typically employ a small telescopic pneumatic cylinder unit which extends between and has the opposite ends thereof coupled to the seat assembly and the chair base. The cylinder unit is a self-contained unit which normally remains in a locked condition but has a valve release pin projecting slidably from one end thereof so that depression of the valve release pin unlocks the cylinder unit and permits it to telescopically extend or contract. The cylinder unit, when the valve is released, is designed to cause upward movement of the seat assembly when the seat assembly is unoccupied or at least a significant portion of the user's weight is removed therefrom, whereas the cylinder unit will contract to lower the seat assembly when the latter has the user's weight imposed thereon and the valve is released. The valve release pin is normally positioned at the upper end of the cylinder unit directly adjacent and substantially within the lower central portion of the seat assembly, and a manually-activated control linkage extends therefrom to a position adjacent the peripheral edge of the seat assembly so as to be manually accessible by the user. Chairs of this general type, and specifically pneumatic cylinder units for height-adjusting mechanisms of the above-described type, are conventional and well known.
At the present time, the control linkage for depressing the valve release pin, in one commonly available form, comprises an elongated actuating lever which is positioned directly adjacent the underside of the seat assembly and has the inner end disposed for cooperation with the valve release pin. The activating lever projects outwardly and is provided with a knob on the outer free end. This knob is normally positioned under the seat assembly but in close proximity to the outer periphery of the seat adjacent one side thereof so as to be accessible by the chair occupant by reaching downwardly and thence inwardly to permit grasping of the knob. While this type of activating lever is functionally satisfactory, nevertheless this elongated lever is, at least in its majority, wholly visible since it is positioned below the bottom shell of the seat assembly. This type of control mechanism hence is aesthetically undesirable, and thus most chair manufacturers attempt to avoid use of such mechanisms on quality chairs.
To avoid use of exposed activating levers of the type described above, there has also been adopted and utilized a control linkage which is positioned substantially internally of the seat assembly so as to be virtually nonvisible to the user of the chair, and hence improve the aesthetics thereof. This known linkage again typically employs an elongated rigid lever which extends from the valve release pin to a position disposed adjacent the periphery of the chair, although the lever is positioned interiorly of the seat assembly, such as by being disposed above the lower seat shell. The outer end of the lever is typically positioned directly over a small actuating button which is supported on and projects downwardly through the lower seat shell adjacent one side of the seat assembly. With this linkage, the user must extend his arm downwardly and thence sidewardly so that the fingers can engage the push button, whereupon the push button must be pushed upwardly to activate the lever, which in turn activates the valve release pin. While this mechanism is utilized in numerous chairs, it nevertheless possesses recognized disadvantages. For example, positioning of the linkage entirely within the interior of the seat assembly often creates space and mounting problems. Further, and more significantly, activation of the linkage by the user is somewhat difficult since the user must stretch his arm downwardly and then sidewardly beneath the seat assembly, and then engage the button with the fingers of the hand and press the button substantially vertically upwardly so as to activate the linkage. This overall position of the hand, and the requirement that the button then be pushed upwardly, hence results in a position which is less than optimum in terms of comfort and control as regards user activation.
Accordingly, it is an object of this invention to provide an improved manually-activated control for a fluid height-adjusting mechanism for a chair, which control is believed to significantly overcome and improve upon the disadvantages associated with known control linkages, as explained above.
Accordingly, this invention relates to an improved manually-activated control for a fluid height-adjusting mechanism, as aforesaid, which is believed to meet the needs of the chair user by providing more desirable access and ease of use, which hence simplifies the adjustability of the height function, and which is aesthetically complimentary to the chair.
A further object of the invention is to provide an improved control, as aforesaid, which can be activated by a natural outward rolling of the user's wrist, and can be activated with minimal force.
A still further object is to provide a control, as aforesaid, which employs a small cuplike control lever pivotally supported and positioned adjacent the outer periphery of the lower seat shell adjacent one side of the seat assembly, which control lever has a cup-shape which permits insertion of several fingers so that the lever can be readily pivoted downwardly and then outwardly toward one side of the seat assembly by a natural outward rolling movement of the user's wrist, which lever is coupled to one end of an elongated flexible element which at its other end is coupled to an interior lever which activates the valve release pin, whereby all of the control is hidden above the lower seat shell except for a small portion of the control lever.
Another object is to provide a control, as aforesaid, which can be manufactured and assembled easily and economically, which can be retrofitted to many existing chairs, which can be utilized comfortably and safely by the user, and which blends in and compliments the overall aesthetics of the chair.
In the present invention, there is provided a pedestal-type chair having a pneumatic height-adjusting mechanism connected between the base and seat assemblies. The seat assembly, as is substantially conventional, includes a cushion supported on an inner seat shell, an inner support frame positioned below the inner seat shell, which support frame normally comprises a part of a conventional chair control, and a lower seat shell which encloses the chair control. A conventional pneumatic cylinder unit (i.e., an air spring) is connected between the base and seat assemblies to permit adjustment in the height of the seat assembly. The air spring has telescopic upper and lower portions coupled to the base and seat assemblies, respectively. The air spring has a valve release pin which slidably projects axially from its upper end so as to be generally accessible from above the lower seat shell. A manually-activated control mechanism extends from the valve release pin internally of the seat assembly to a location disposed adjacent the periphery of the seat assembly to permit manual release of the cylinder unit when adjustment of the chair height is desired. This control mechanism includes a small manually-engageable activating lever which is pivotally supported interiorly of the seat assembly and positioned so as to project slightly downwardly a small extent through the lower seat shell adjacent one side of the seat assembly. This activating lever is pivotally supported for swinging movement about an axis which is positioned outermost and extends approximately parallel to one peripheral side of the seat assembly. The lever projects generally inwardly from the pivot axis toward the cylinder unit and defines a small cuplike recess which opens generally toward the cylinder unit, which recess is accessible directly adjacent and from below the lower seat shell so as to receive therein the ends of about three fingers. The lever has a small cable drum thereon in concentric relationship to the pivot axis, and one end of elongated flexible cable is anchored to this cable drum. An intermediate bell crank lever is pivotally supported on the interior support frame of the chair interiorly of the seat assembly in the lower central portion thereof. This bell crank has one lever arm thereof disposed for activating the valve release pin, and the other arm thereof is coupled to the other end of the cable, which cable is disposed interiorly of the seat assembly. To activate the valve release pin, the user positions the arm downwardly along the side of the chair seat and bends the arm inwardly so that the hand is positioned under the lower seat shell adjacent the periphery thereof. This hence enables the user to insert three fingers into the cuplike recess of the lever, and by placing the palm of the hand against the adjacent outer shell, the user can then roll his wrist outwardly to effect pivotal swinging movement of the activating lever downwardly and outwardly about its pivot axis. This effects a partial winding of the cable onto the cable drum, which in turn activates the bell crank lever so as to depress the valve release pin.
Other objects and purposes of the invention will be apparent to persons familiar with structures of this general type upon reading the following specification and inspecting the accompanying drawings.